The Staudinger synthesis, named after the German chemist Hermann Staudinger

Hermann Staudinger

- External links :* Staudinger's * Staudinger's Nobel Lecture *....

, is a method to prepare β-lactam

Beta-lactam

A β-lactam ring, is a four-membered lactam. It is named as such, because the nitrogen atom is attached to the β-carbon relative to the carbonyl...

s. An imine

Imine

An imine is a functional group or chemical compound containing a carbon–nitrogen double bond, with the nitrogen attached to a hydrogen atom or an organic group. If this group is not a hydrogen atom, then the compound is known as a Schiff base...

 reacts with a ketene

Ketene

A ketene is an organic compound of the form R'RC=C=O. The term is also used specifically to mean ethenone, the simplest ketene, where R' and R are hydrogen atoms.Ketenes were first studied as a class by Hermann Staudinger.-Formation:...

 in a formal [2+2]-cycloaddition

Cycloaddition

A cycloaddition is a pericyclic chemical reaction, in which "two or more unsaturated molecules combine with the formation of a cyclic adduct in which there is a net reduction of the bond multiplicity." The resulting reaction is a cyclization reaction.Cycloadditions are usually described by the...

 to give the cyclic amide.

History

The reaction was discovered in 1907 but did not attract much interest until the 1940s, when the structure of penicillin

Penicillin

Penicillin is a group of antibiotics derived from Penicillium fungi. They include penicillin G, procaine penicillin, benzathine penicillin, and penicillin V....

was elucidated. The β-lactam moiety of the first synthetic penicillin was constructed using this cycloaddition, and it remains a valuable tool in synthetic organic chemistry.